Field of the Invention
The present invention relates to a wireless communication system, and more particularly, to a method of performing beamforming training and an apparatus using the same.
Related Art
An IEEE 802.11ad standard is a very high-speed wireless communication standard that operates in a band of 60 GHz or above. Even though a signal can reach about 10 meters, the throughput may support 6 Gbps or more. Since the IEEE 802.11 ad standard operates in a high frequency band, signal propagation is dominated by ray-like propagation. As a transmit (TX) or receive (RX) antenna beam is arranged toward a strong spatial signal path, signal quality thereof may be improved.
The IEEE 802.11ad standard includes a beamforming training process for antenna beam alignment. To achieve throughput of 20 Gbps or more, a next-generation standard that is being developed on the basis of the IEEE 802.11ad is called as an IEEE 802.11ay. One of the key technologies of the IEEE 802.11ay is a multiple input multiple output (MIMO) beamforming technology through an array antenna. The IEEE 802.11ad as a conventional technology supports a single stream transmission using one array antenna, and a next-generation technology (e.g. IEEE 802.11ay) thereof supports multi-stream transmission using a plurality of antenna arrays.
To apply the plurality of array antennas, it is required that a plurality of independent beamformings are performed. However, this may cause severe interference between a plurality of streams and an increase of time required for the beamformings. A method will be proposed to minimize the interference between the streams and reduce the time required for the beamformings.